Sunday, December 19, 2010

Potato Diet Interpretation

If you read my post on December 16th, you know that Chris Voigt saw remarkable fat loss and improvements in health markers as a result of two months of eating almost nothing but potatoes. This has left many people scratching their heads, because potatoes are not generally viewed as a healthy food. This is partially due to the fact that potatoes are very rich in carbohydrate, which also happens to be a quickly digested type, resulting in a high glycemic index. The glycemic index refers to the degree to which a particular food increases blood glucose when it's eaten, and I've questioned the relevance of this concept to health outcomes in the past (1, 2, 3). I think Mr. Voigt's results once again argue against the importance of the glycemic index as a diet-health concept.

It's often pointed out that potatoes are low in vitamins and minerals compared to vegetables on a per-calorie basis, but I think it's a misleading comparison because potatoes are much more calorie-dense than most vegetables. Potatoes compare favorably to other starchy staples such as bread, rice and taro.

Over the course of two months, Mr. Voigt lost 21 pounds. No one knows exactly how much of that weight came out of fat and how much out of lean mass, but the fact that he reported a decrease in waist and neck circumference indicates that most of it probably came out of fat. Previous long-term potato feeding experiments have indicated that it's possible to maintain an athletic muscle mass on the amount of protein in whole potatoes alone (4). So yes, Mr. Voigt lost fat on a very high-carbohydrate diet (75-80% carbohydrate, up to 440g per day).

On to the most interesting question: why did he lose fat? Losing fat requires that energy leaving the body exceed energy entering the body. But of course, that's obvious but it doesn't get us anywhere. In the first three weeks of his diet, Mr. Voigt estimates that he was only eating 1,600 calories per day. Aha! That's why he lost weight! Well, yes. But let's look into this more deeply. Mr. Voigt was not deliberately restricting his calorie intake at all, and he did not intend this as a weight loss diet. In my interview, I asked him if he was hungry during the diet. He said that he was not hungry, and that he ate to appetite during this period, realizing only after three weeks that he was not eating nearly enough calories to maintain his weight*. I also asked him how his energy level was, and he said repeatedly that it was very good, perhaps even better than usual. Those were not idle questions.

Calorie restriction causes a predictable physiological response in humans that includes hunger and decreased energy. It's the starvation response, and it's powerful in both lean and overweight people, as anyone knows who has tried to lose fat by decreasing calorie intake alone. The fact that he didn't experience hunger or fatigue implies that his body did not think it was starving. Why would that be?

I believe Mr. Voigt's diet lowered his fat mass 'setpoint'. In other words, for whatever reason, the diet made his body 'want' to be leaner that it already was. His body began releasing stored fat that it considered excess, and therefore he had to eat less food to complete his energy needs. You see this same phenomenon very clearly in rodent feeding studies. Changes in diet composition/quality can cause dramatic shifts in the fat mass setpoint (5, 6). Mr. Voigt's appetite would eventually have returned to normal once he had stabilized at a lower body fat mass, just as rodents do.

Rodent studies have made it clear that diet composition has a massive effect on the level of fat mass that the body will 'defend' against changes in calorie intake (5, 6). Human studies have shown similar effects from changes in diet composition/quality. For example, in controlled diet trials, low-carbohydrate dieters spontaneously reduce their calorie intake quite significantly and lose body fat, without being asked to restrict calories (7). In Dr. Staffan Lindeberg's Paleolithic diet trials, participants lost a remarkable amount of fat, yet a recent publication from his group shows that the satiety (fullness) level of the Paleolithic group was not different from a non-Paleolithic comparison group despite a considerably lower calorie intake over 12 weeks (8, 9). I'll discuss this important new paper soon. Together, this suggests that diet composition/quality can have a dominant impact on the fat mass setpoint.

One possibility is that cutting the wheat, sugar, most vegetable oil and other processed food out of Mr. Voigt's diet was responsible for the fat loss. Many people find, for example, that they lose fat simply by eliminating wheat from their diet.

Another possibility that I've been exploring recently is that changes in palatability (pleasantness of flavor) influence the fat mass setpoint. There is evidence in rodents that it does, although it's not entirely consistent. For example, rats will become massively obese if you provide them with chocolate flavored Ensure (a meal replacement drink), but not with vanilla or strawberry Ensure (10). They will defend their elevated fat mass against calorie restriction (i.e. they show a physiological starvation response when you try to bring them down to a lower weight by feeding them less chocolate Ensure) while they're eating chocolate Ensure, but as soon as you put them back on unpurified rodent pellets, they will lose fat and defend the lower fat mass. Giving them food in liquid or paste form often causes obesity, while the same food in solid pellet form will not. Eating nothing but potatoes is obviously a diet with a low overall palatability.

So I think that both a change in diet composition/quality and a decrease in palatability probably contributed to a decrease in Mr. Voigt's fat mass setpoint, which allowed him to lose fat mass without triggering a starvation response (hunger, fatigue).

The rest of his improvements in health markers were partially due to the fat loss, including his decreased fasting glucose, decreased triglycerides, and presumably increased insulin sensitivity. They may also have been partially due to a lack of industrial food and increased intake of certain micronutrients such as magnesium.

One of the most striking changes was in his calculated LDL cholesterol ("bad" cholesterol), which decreased by 41%, putting him in a range that's more typical of healthy non-industrial cultures including hunter-gatherers. Yet hunter-gatherers didn't eat nothing but potatoes, often didn't eat much starch, and in some cases had a high intake of fat and saturated fat, so what gives? It's possible that a reduced saturated fat intake had an impact on his LDL, given the relatively short timescale of the diet. But I think there's something mysterious about this setpoint mechanism that has a much broader impact on metabolism than is generally appreciated. For example, calorie restriction in humans has a massive impact on LDL, much larger than the impact of saturated fat (11). And in any case, the latter appears to be a short-term phenomenon (12). It's just beginning to be appreciated that energy balance control systems in the brain influence cholesterol metabolism.

Mr. Voigt's digestion appeared to be just fine on his potato diet, even though he generally ate the skins. This makes me even more skeptical of the idea that potato glycoalkaloids in common potato varieties are a health concern, especially if you were to eliminate most of the glycoalkaloids by peeling.

I asked Mr. Voigt about what foods he was craving during the diet to get an idea of whether he was experiencing any major deficiencies. The fact that Mr. Voigt did not mention craving meat or other high-protein foods reinforces the fact that potatoes are a reasonable source of complete protein. The only thing he craved was crunchy/juicy food, which I'm not sure how to interpret.

He also stopped snoring during the diet, and began again immediately upon resuming his normal diet, perhaps indicating that his potato diet reduced airway inflammation. This could be due to avoiding food allergies and irritants (wheat anyone?) and also fat loss.

Overall, a very informative experiment! Enjoy your potatoes.

*Until the last 5.5 weeks, when he deliberately stuffed himself beyond his appetite because his rapid weight loss worried him. Yet, even with deliberate overfeeding up to his estimated calorie requirement of 2,200 calories per day, he continued to lose weight. He probably was not quite reaching his calorie goal, or his requirement is higher than he thought.

53 comments:

I wonder if the fact that his diet had little variety had anything to do with his results. If I eat the same thing every day, even my favorite foods, I would get sick of them and stop eating them. My brother-in-law subsisted on Snickers bars and Ritz Bits for 10 days once (he was guarding a hotel in New Orleans after Katrina and that's what they had) and he lost weight too.

I have been following this premise for 15 months now. Eating large amounts of unrefined carbs daily (maybe 65% total cals or higher daily). I go through about 20lbs of potatoes per week for example, or 3lbs per day. The only foods I avoid are PUFA's, gluten, soya, and try to keep fructose low. Basically I try to avoid all processed foods, and eat home cooked food as much as possible.

This has brought my fasting BG from 120 to 85 in 3 months. Even after eating large amounts of unrefined carbs or potatoes, BG will only spike to 120 at 2hrs postprandial.

My setpoint has dropped from 196 to 188, with using walking as the only exercise.

Previous to the last 15 months, I was very low carb for 1 year, that didn't go so well...

Weston Price found many of cultures in supreme health utilizing unrefined carbs, and the potato was definitely one of them. Actually I think the only cultures that were not are the Inuit and the Masai.

With regard to his cholesterol results, if he was releasing stored fat back into systemic circulation, this body fat would have been a mixture of SFA & MUFA. Would this have not then had the same effect as feeding dietary SFA? Increased HDL and a possible shift in LDL/particle size?

Lots of interesting parallels between Haub on the Twinkie Diet and Voigt on the Potatoe Diet. Both are in the same age and demographic, and both have stated that they believe that body weight is determined by "calories in vs. calories out". However, counter to this belief, they also both lost about the same amount of weight over the same period of time, but Voigt ate about 15-30% more calories during this time.

Voigt claimed on Moore's LLVLCS podcast that he'd "never heard of anti-nutrients in potatoes", which also sounds like a bit of a stretch given his profession deals with potatoes. His focus is on marketing, so I guess I can believe that. But Haub's claim that hunger and energy levels weren't an issue on his diet, I have a much harder time believing that. At six or seven twinkies a day I think I'd be so ravenous that I'd be ready to stab someone's eyes out and eat them after just a week on that diet.

... I avoid all animal products and all "seeds" (legumes, grains, nuts, etc.). I eat about 25 pounds of starchy "roots" per week: sweet potatoes, American yams, rutabagas, and (mostly) Russet potatoes, as well as other starches such as winter squash. I also eat plenty of vegetables and fruit. The one nutrient missing is B12, for which I take a supplement.

I have been eating this way for six years. At 66, I am thriving on my root-starch centered diet. Medical tests (CAT scan, heart monitor, X-rays, blood tests, etc.) have revealed no problems: no heart disease, cancer, diabetes, osteoporosis, kidney problems, or others. My past inflammation problems are gone. My eyesight has returned to what it was around 1983. I sleep well. I walk two hours per day and climb stairs. I have a big appetite (three large meals, with no snacks).

Would I recommend this diet to everyone? Not at all. But it does work well for me and the problems I had.

Thank you for the article. It helps confirm that potatoes are not an evil food. They do not belong in the category that includes pop and donuts.

This potato diet reminds me of Tim Ferriss' new book The 4 Hour Body. One of his self experimentations for fat loss is to eat the same few meals over and over again. I haven't read the book yet so I guess he did lose fat.

I think any marked choice reduction can bring weight loss. One professor lost weight on the Twinkie diet (granted he did conciously calorie restrict). I think Atkins was initially more effective because there was little quick packaged food so it was effort to find the allowed food to eat. As marketers filled the niche for quick/easy/diverse Atkins food, the diet's effectiveness waned. Variety is the spice of life, but may not help the waistline.

We note significant differences in how men and women lose weight, and there is some evidence that genetic factors may be at work too; see Interleukin Genetics' explanation of their test for genetic markers for the types of foods that cause weight gain. I blogged about WSJ article, now behind a paywall, that revealed using the test on 133 women resulted in better weight loss without the "outliers" that didn't lose any weight (typically, weight loss studies end up out out-performers, moderate losers, and those that don't lose or even gain weight in each of the diets tested.)

It doesn't surprise me that some people would respond well to foods other's don't.

Chris Voight was 6'2 and 195 pounds before starting the diet. He had no diseases, I'm presuming. He was a healthy relatively young person.

I've said it before, I'll say it again. YOU CAN NOT compare the endocrine system, neurotransmitter profile, and metabolism of a healthy person to that of a person who has clear cut illness. If I tried the "all potato" diet, I would not do well. I have a clear cut metabolic/neuroendocrine disorder vulnerability.

If I eat nothing but peanuts for 2 weeks and feel fabulous afterward, does this somehow disprove that a certain subset of the population becomes anaphylactic in response to eating it?

I'm a RN with two years experience in a subacute facility. I have taken care of many patients with CLEAR CUT metabolic syndrome of moderate or severe intensity. It becomes obvious to me, after taking care of these patients, that something is very very very wrong with their bodies and it isn't caused by their diets. If it was caused by eating some magic food (or not) then all of us would end up with a very large belly, diabetes, hypertension, and severe heart disease. But no, we don't all end up that way. It clusters in families, it tends to strike in middle age. It's also quite clear that early onset obesity (youth, teens, 20s) is not entirely related to middle aged metabolic syndrome, as those with middle aged metabolic syndrome are rarely extremely obese (they are often overweight though).

Again, you can take relatively thin, young, disease free people and feed them sugar and potatoes and whatever you want. It proves absolutely nothing. You have to test people who actually have the physical disorders you are trying to understand.

My diet is not the reason I had severe obesity before 20 years old, severe PCOS, reactive hypoglycemia, bad cholesterol and all these problems. Diet exacerbated or triggered it perhaps, but this is entirely something biological, it is the way my body works (or rather, fails to work). It appears quite genetic and heritable, it is in my family tree many generations (reproductive problems and signs of metabolic disorder). The same is true of others with weight/metabolic/health problems. They cluster. These things are heritable.

There is no magic food. I encourage everyone who is interested in such things to work with REAL patients for a few months or years. Volunteer at a rehab or a hospital. It becomes very very obvious this is an illness and it isn't caused by food, only perhaps triggered or exacerbated by it.

Oh and this guy is head of the "potato comission". How truthful can we take his claims of effortless weight loss no hunger and a complete turn around in personality by eating nothing but potatoes? This DEFIES logic. An all potato diet is hardly nutritionally complete, it's intuitive that a person would feel like crap eating nothing but potatoes.

I've been reading this blog for like, over a year, and it's obvious you really like potatoes. It's like your mission to get everyone to conclude that potatoes are fine for everyone to eat, all the time. LOL. If you like starchy tubers, that's great...but you need to accept that some people don't do well on them. People with glucose/metabolic/endocrine issues can't eat a lot of potatoes, unless they are on semistarvation level cals or doing tons of physical activity or something like that. End of story. Food like eggs I can eat no matter what my calories or my activity. Glucose food is something that I have to handle with care because my metabolism, neuro-endocrine system does not work properly.

I'm a bit hesitant to accept, at face value, that he lost the majority of his weight as fat. Simply losing inches on his neck and waist could indicate with fat or lean mass loss. Harder numbers with respect to this would have been helpful!

The objective results (weight loss, trigs, etc.) seem impressive from the outside, but let's remember that anyone eating 1600 calories of ANYthing will lose weight. And anyone who loses weight lowers their LDL, regardless of the source. Whether LDL even matters for health is another question entirely.

But Itsthewooo implies, the subjective results such as hunger factors and sleep quality are to be taken with more than a grain of salt when they come from a guy who's whole career and industry depends on consumers believing that potatoes are good for you.

And don't forget: 2 months does not a whole lifetime make. Will he be thriving in 2 years, after his body is fully depleted of essential minerals, fats and vitamins? I doubt it. It's impulsive and reductionist (and ultimately dangerous) to extrapolate a lifetime's health from a 2-month diet trial, in my opinion.

This all begs the question of whether we should we be using weight loss and LDL as health markers at all.

Do you think that 'palatability' can radically vary even in the same person. e.g. when I was on a standard low fat/high carb diet a dessert spoon of cream would taste ludicrously rich. Yet after a little while on a high fat diet I drink glasses of cream or eat blocks of butter (and find the butter pretty bland) without blinking, but find that eating a whole sweet potato seems like a feast and hits the bloodstream like a train.

Also I second Jamie Scott's point- if he was at least 600 calories short per day, wasn't he in effect consuming quite a bit of (his own) animal fat? (Equivalent to eating almost 100g of butter on his potatos per day.)

Oh and btw three weeks is about how long I could easily restrict calories and not notice any ill effect (as I did when I was conventionally trying to lose weight in the past). I would want to see how Chris fared after this period eating only potatoes. I also found that my body could be fooled by low quality/high fibre foods for a limited period of time (e.g. feeling full on a 200 calorie serving of chickpeas), but eventually the body smartens up and decides that you need more calories.

ItsTheWooo2 is misreading Stephan. If you actually are a regular reader, you should know that one of his foci is what causes the diseases of civilization. He has stated many times that once your metabolism is messed up, then low-carb is likely a good idea for you.Also, nobody is suggesting that we put WIC mothers on a potato only diet. Rather, it is ridiculous to not pay for potatoes but to continue to pay for bread. The problem is potatoes being classified as a vegetable.

Informative post. To me, it's obvious that certain industrial foods short circuit satiety signals. For example, I cannot control myself if I have one slice of high quality, crispy cheese pizza-if I have one piece, I desire, and could easily eat, the whole pie. I continue to eat, even if I'm so full it's hard to breathe. In contrast, eating whole foods does not do this. Whether it's a steak, or a baked potato with butter, I eat to fullness and easily stop.

The Shangri-La diet rests on a premise similar to what you are thinking with palatability. Seth Roberts came up with the theory that there is a flavor/calorie association which influences set point. More intense and pleasurable flavors= more appetite.

Works very well too. It's a little weird trying to ingest calories without tasting them, but for the tiny amount of effort and time put in, the effect on appetite is quite large.

As an aside: yesterday I decided to try potatoes. I made potato salad with eggs, celery and parsley, and another batch of potato salad with tuna. (Skipjack in water).

Usually I sleep very restlessly. Last night I fell asleep on my usual right side and I woke up on my back. The bedding indicated that I slept like a log. Usually my bed looks like a war went on all night. I haven't slept this well in ages and ages.

I was reading Siddhartha Mukherjee's 'Biography of Cancer' until midnight. I couldn't put the darn thing down and was concerned that 6 hours of sleep would leave me severely sleep deprived. I woke up feeling well rested. I feel great.

I don't like potatoes. Doesn't matter what kind, Louisiana yams, white sweets, purple sweets.... all the same. But I'll do this and find out if the effects are consistent over time.

Probably 1 liter of coconut water would have the same effect except that stuff is pricey.

Glad to hear you've made progress. There are actually several older studies showing that in certain people, a diet high in unrefined carbohydrate can virtually reverse diabetes. That's why the ADA recommends diets like that. Your beta cells have to be mostly intact for it to work though.

Hi Jamie,

I don't know if burning body fat is the equivalent of eating fat of a similar composition.

Hi bud.ca,

Potatoes are low in anti-nutrients, and the ones it contains are generally denatured by heat, so it doesn't surprise me that Voigt wouldn't be familiar. The toxins potatoes contain are solanine and chaconine, which are not anti-nutrients and which Voigt is probably familiar with.

Hi Itsthewoo,

You've uncovered my diabolical plan to enslave the world and make everyone eat nothing but potatoes! Drat.

Keep in mind that Voigt started off with a fasting glucose of 104. Overall, his pre-diet numbers suggested that he might be on the path to diabetes and CHD.

Hi Gunther,

Remember that Voigt's results are consistent with longer-term potato feeding trials (6 months and a year) in which the volunteers apparently did not lose an appreciable amount of muscle mass (as judged by nitrogen balance and physical appearance). Also, there are cultures that eat practically nothing but potatoes that I've written about. I'm not saying that's an ideal diet, simply that it doesn't lead to the dire consequences that some people predict.

As far as Voigt's truthfulness, I'm operating under the assumption that he's being truthful. I've communicated with him several times, and my gut feeling is that he's being truthful. Either that, or he's a good actor, but that would surprise me. He didn't embark on this to show people that potatoes cause fat loss. In fact, he explicitly didn't want to send that message because he doesn't want people eating nothing but potatoes as the next diet craze. That's why he upped his calorie intake 3 weeks into it.

Hi Ned,

Neck circumference reflects both lean and fat mass, so that doesn't allow us to differentiate very well, but waist circumference is almost purely a reflection of fat mass.

Hi August,

I'm currently learning about Roberts' theory, but suddenly it seems plausible to me.

Hi Gabriella,

Good point, some of the weight loss could have come from water if he had a reduced salt intake. I don't know if he reduced his salt or not, I should have asked that.

"And anyone who loses weight lowers their LDL, regardless of the source"

I'm not trying to start a message board war - not only because I agree with almost everything you wrote - but a lot of people like myself who switch from the SAD to eating high fat, low carb see an increase in LDL while losing fat. Just check the message board at Mark's Daily Apple, there are plenty of people posting about it.

After doing Crossfit for about a year and eating "healthy" I just couldn't lose any more belly fat. I switched to eating a Paleo based diet (with some dairy, no fear of sat fat) and I lost an additional 24Lbs of fat, all from my gut, but my LDL went from calculated 177 (probably more like 159 due to low triglycerides) to a VAP measured 243.

Hmm... so it looks like potatoes do not mess up insulin and leptin signaling, at least not for Chris Voigt. 21 lbs over about 60 days is an average of 1225 fat calories a day deficit. I wonder what his body composition was when it started.

1600+1225 is 2825 basal metabolic rate, working backwards with Katch-McArdle BMR formula, he'd started at 113kg lean body mass, or 250lbs lean body weight. But, his website says he started at 197lbs.

Roberts' theory seems like a very plausible way to lose weight in the short term, as do many other methods like using smaller plates, eating unusual foods, hanging out with people that eat less, eating food that is not calorically dense, etc. I've always been curious how long these methods can "fool" the body. Do you think these techniques really lead to a long term resetting of the set point, or just a short term trick whereby the body is temporarily "unaware" or unconcerned that weight has dropped below the setpoint? Put another way, do you think palatability reduction is a legitimate long term weight loss strategy?

I phoned my daughter yesteday. She was home with a bad cold. Lots of productive sticky mucous. She didn't have any ginger in the house. In the process I told her about this potato business.

Being my kid, she ate potatoes last night for supper. She slept the best yet with this awful cold she's had. And today her cough is negligible. Maybe Voigt had an important observation about how he didn't pick up on any of the colds and viruses going around: no snoring, no mouthbreathing, no drying out of mucous membranes, no inflammtion of the breathing tract and no vulnerability to virus particle establishing themselves.

All very very cool stuff.

I'm beginning to wonder if asthma sufferers would benefit from eating potatoes and other potassium rich foods. Oh, I'm sure it's mentioned somewhere out there in internetland.

Our perception of how "juicy" a food is is a function of a couple of things. I'm trying to remember the details, from On Food And Cooking. I believe that water content accounts for 1/3rd of the juicyness perception. Acidity/tanginess I believe is more important, because it stimulates salivary flow. I think salt may also be related, but I'm not sure. If someone can find their copy of On Food And Cooking, he explains it all.

I think it's important to note that the postmenopausal women cited in that study showing benefit the more sat fat they ate were on a relatively low fat diet (<25%).

It could be that eating sat fat has one effect when you're on a low-fat diet and another effect when you're on a low-carb, high-fat diet.

It's easy for the public and even some health care people to misgeneralize. When high-carb diets first became popular, and the idea was that you replaced fat with carbs, one nutrition writer wrote "The more carbs the better," as if it was increasing carbs, not reducing fats, that was the goal. So some people thought if you ate a standard American diet and then added a huge load of carbs, you'd be fine.

Without specifics, some people reading about the postmenopausal women study might think the more fat you ate, the better.

Losing weight while forcing yourself to eat more potatoes would probably not surprise Dr. Susanna Holt and her associates at the University of Sydney, the developers of the Satiety Index:http://www.mendosa.com/satiety.htmPotatoes have by far the highest index on the published table and are the most satisfying (although I guess sweet potatoes and Yams are similar but they haven't been tested yet).This would probably explain the low calorie intake of the Okinawa centenarians on their traditional sweet potato diet.Jay Bryant

I used to be the type of person who needed a lot of variety in my diet. The thought of eating the same things for even a week in a row would make me feel a little nauseous. No way, I thought.

Then severe health issues and widespread allergies hit me.

And after eating potatoes and red meat (beef, mostly) fixed the same way for each meal the past several years I can say with confidence that no matter what you may think, if you're getting the proper nutrients your body *does* adjust to an extremely limited diet. Though I thought I would, once I adjusted I did not "get sick" of the food, I have not experienced "appetite fatigue", and in fact I've come to wonder if we really need as much variety as modern nutritional experts claim.

When you're eating for the taste of a variety of things it seems you're much more likely to overeat, to stuff yourself more full than you should. Avoiding that takes mental effort and self-discipline. My food tastes good to me every time I eat it, but because I'm eating exactly the same thing there is zero issues with eating too much. And because I enjoy the taste there is no problem of eating too little. My intake changes only depending on my body's need and nothing else. Though unintentional, these factors simplify my life considerably.

I'm a bit surprised that so many people think that if you narrow your diet to one or two things you'll automatically eat less than your body needs. That has not been my experience nor, it seems, has it been that of others.

Because I was kind of curious I tried going on a potato only diet. I baked my potatoes with a thin coating of olive oil on the outside, so salt would stick. Other than that I ate nothing but potato and salt.

The first potato I ate sent my blood sugar to a whopping 220. I felt tired, and achy all day long. The second day my blood sugar was going up to about 170 after a potato (7-8 oz), so it did improve some. I still felt really tired and sleepy all day long.

I only lasted two days. Gained 1 pound even though I ate less than my BMR. About 1200 calories.

That he stopped snoring on potatoes-only could be due to removing foods to which he has food sensitivities, not to some benefits of potatoes. It is too bad he didn't reintroduce foods one at a time to see when the snoring started again.

Very low-fat diets (10-15%) and low-protein (10%) diets typically do increase insulin sensitivity. When I was on a different low-fat diet (Graham's 80-10-10) my blood sugar regulation was better than it had been for years, with fasting blood glucose of 83, peaks of 120, and getting back to 83 in 2-3 hours after eating. Graham's diet is high fructose, though, so I eventually stopped because of the effect on my nitric oxide metabolism.

Part of the increased insulin sensitivity of low-fat/protein diets is probably because the body needs to secrete higher levels of insulin to clear protein than to just clear the same number of calories of glucose.

Stephen, tx for a great blog forum. Very interesting "case study". And while weight loss is an admirable goal.... what's one's real goal - weight loss in itself or long term health & viability? I really gotta question, over the life span - a "spud" based program. It does illustrate the relative "safety" of potatoes in the diet..verses say wheat, gluten based grains & legumes – for his particular genotype. But nutritionally, over a life span – count on malnutrition and maybe being thinner. I wouldn’t be able to tolerate that high of a carb diet… no wheat, gluten grains or legumes plus low carb & high animal fat (pasture meats, dairy fat, coconut milk/fat) is what allowed me to lose a bit of a spare tire (8#s/122# body), reduce inflammation and maintain my muscle mass while eating 4000 kcals per day the first 6 months! As a 52yo female, I have TRIG 53, HDL 80, A1c 5.4, body fat 16%. Taubes, WPF & paleo combined - adjust for your genotype, add water & go. Vive Vida!

I really think some of his health improvements might have been due to the massive amount of potassium and low amount of sodium he was ingesting. According to NutritionData.com, 1 calorie of a baked potato with skin has 5.755 mg of potassium. Assuming he ingested 2200 calories a day, he was ingesting 12661 mg of potassium a day. The USRDA of potassium is 3500 mg, so he was ingesting 3.62 TIMES the USRDA for potassium. This 12 grams a potassium a day is a lot, and I am sure had major physiological effects.

It's unfortunate that Mr. Voigt just didn't have enough appetite to keep himself out of the caloric restriction range (who could blame him -- eating potatoes all day). Because now we're left with the question as to how much of his LDL improvement was merely reflective of CR, and how much was in fact due to the mere elimination of grain or other nasties from his diet. Correct me if I'm wrong, but I recall that you said the Kitavan have somewhat elevated LDL levels, which may or may not result from their smoking habits. So in fact, it could be that full-calorie high-carb diets actually increase LDL (and atherosclerotic plaque formation), even though they don't necessarily lead to diabetes.

The very existence of the Irish Potato Famine suggests that these people were heavily dependent on potatoes, and thus may have been somewhat calorically restricted even in times of good harvest. This would explain their "good looks" documented in historical texts.

The whole theory that a normally functioning insulin system can deal safely with high glycemic load is compelling, as is the idea that grains' lectins, gluten, and phytic acid can throw a wrench in the works. But is it possible that such high-carb grainless diets may induce a higher rate of LDL oxidation than the calorically equivalent lipid-based diet? In other words, is it possible that they raise CHD risk without actually raising the risk of diabetes? So the Kitavans' elevated LDL might in fact be due to their full-calorie high-carb diet. But if that's the case, then there must be something protecting them from CHD (HDL?). This fascinating experiment of Mr. Voigt's raises more questions than it answers. But the tempting conclusion that high-carb grainless diets are as good as any full-calorie diet may not be true. In any event, this was an entirely worthwhile read.

I've recently begun a more vegetarian diet, cutting out land based meats for more vegetables and sometimes fish. I've been eating more fruits for a while now, but now that I'm eating mostly vegetables and grains, I've begun to REALLY crave fruits. I didn't have any in the house earlier and I absolutely HAD to walk to the store to go buy some. It's a bit of a walk, and not a trip I would normally make if I were just hungry.I'm not a nutritionist, but is there something in fruits he craved, perhaps? I immediately thought "apples" when I read "juicy and crunchy"....

So now we have Andrew "Spudfit" Taylor who has completed 6 months of eating almost entirely potatoes. He has documented his results with a dexa scan and doctors appointments on youtube. Gives even more credibility to what Voight did.

About Me

I'm a writer and science consultant with a background in neuroscience and obesity research. I have a BS in biochemistry and a PhD in neurobiology. I'm the author of "The Hungry Brain: Outsmarting the Instincts That Make Us Overeat".

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3) Do not use it for commercial purposes

Financial disclosure

I am a co-creator of the Ideal Weight Program, and I receive revenue from the sale of this program.

In addition, I am registered as an Amazon affiliate. I may receive a small commission on the sale of some of the books I review, or other products sold through Amazon.

Disclaimer

This blog is a compilation of my opinions. It's not advice; it's information that you can take or leave as you please. I don't intend it to replace professional medical consultation or treatment. Your health is in your own hands.